拉索风雨激振的多模态耦合及面内-面外振动

在假设拉索表面与水线之间作用着库仑阻尼力和粘滞线性阻尼力的基础上，建立了能够反映拉索面内-面外振动的带运动水线的连续弹性拉索风雨激振理论模型。通过振型分解，获得了以拉索面内-面外各阶模态表示的拉索运动微分方程。利用该理论模型对洞庭湖大桥S19拉索进行了分析，结果表明：拉索风雨激振是多模态的耦合振动，振动过程中伴随着模态的转移；面内振动和面外振动同时发生，通常情况下面内振动占据优势；拉索截面运动的轨迹是一个斜置椭圆，或是几个斜置椭圆交织在一起；风速对拉索振动偏振角有较大影响；拉索最大振幅发生的位置随参振模态的变化而改变

Modes coupling and in-plane/out-of-plane vibration in rain-wind induced vibration of cable

Assuming the interactions between cable surface and rivulet as the synthesized Coulomb and linear viscous damping forces,the in-plane/out-of-plane rain-wind-induced vibration model of continuous elastic cable with moving rivulet was formulated.Differential equations of motion expressing in-plane and out-of-plane modes of cable vibration were obtained through modes decoupling method.S19 cable of Dongting Lake Bridge was analyzed using this model.It is shown that rain-wind-induced vibration of cable includes several modes which are coupled and transformed mutually.The in-plane-vibration and the out-of-plane-vibration occur at the same time and the in-plane-vibration occupies dominant position generally.Vibration locus of cable’s section is an inclined ellipse or several inclined ellipsis which are interlaced with each other.Wind velocity has an important effect on inclination angle of cable vibration.The location of maximum amplitude is changed along with different vibration modes.